[AVR32] NMI debugging
Change the NMI handler to use the die notifier chain to signal anyone
who cares. Add a simple "nmi debugger" which hooks into this chain and
that may dump registers, task state, etc. when it happens.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
diff --git a/arch/avr32/kernel/nmi_debug.c b/arch/avr32/kernel/nmi_debug.c
new file mode 100644
index 0000000..3414b85
--- /dev/null
+++ b/arch/avr32/kernel/nmi_debug.c
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2007 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/delay.h>
+#include <linux/kdebug.h>
+#include <linux/notifier.h>
+#include <linux/sched.h>
+
+#include <asm/irq.h>
+
+enum nmi_action {
+ NMI_SHOW_STATE = 1 << 0,
+ NMI_SHOW_REGS = 1 << 1,
+ NMI_DIE = 1 << 2,
+ NMI_DEBOUNCE = 1 << 3,
+};
+
+static unsigned long nmi_actions;
+
+static int nmi_debug_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ struct die_args *args = data;
+
+ if (likely(val != DIE_NMI))
+ return NOTIFY_DONE;
+
+ if (nmi_actions & NMI_SHOW_STATE)
+ show_state();
+ if (nmi_actions & NMI_SHOW_REGS)
+ show_regs(args->regs);
+ if (nmi_actions & NMI_DEBOUNCE)
+ mdelay(10);
+ if (nmi_actions & NMI_DIE)
+ return NOTIFY_BAD;
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block nmi_debug_nb = {
+ .notifier_call = nmi_debug_notify,
+};
+
+static int __init nmi_debug_setup(char *str)
+{
+ char *p, *sep;
+
+ register_die_notifier(&nmi_debug_nb);
+ if (nmi_enable()) {
+ printk(KERN_WARNING "Unable to enable NMI.\n");
+ return 0;
+ }
+
+ if (*str != '=')
+ return 0;
+
+ for (p = str + 1; *p; p = sep + 1) {
+ sep = strchr(p, ',');
+ if (sep)
+ *sep = 0;
+ if (strcmp(p, "state") == 0)
+ nmi_actions |= NMI_SHOW_STATE;
+ else if (strcmp(p, "regs") == 0)
+ nmi_actions |= NMI_SHOW_REGS;
+ else if (strcmp(p, "debounce") == 0)
+ nmi_actions |= NMI_DEBOUNCE;
+ else if (strcmp(p, "die") == 0)
+ nmi_actions |= NMI_DIE;
+ else
+ printk(KERN_WARNING "NMI: Unrecognized action `%s'\n",
+ p);
+ if (!sep)
+ break;
+ }
+
+ return 0;
+}
+__setup("nmi_debug", nmi_debug_setup);